ggplot facet_wrap different themes

Question

I am looking for a way to facet_wrap different themes in the same %>% line, to get something like

Is there any way to do something similar without having to do

fig1 = mtcars %>% filter(am == 1) %>%
  ggplot(aes(wt, mpg)) +
  geom_point() + 
  theme_bw(base_size = 15) + ggtitle('Theme A')

fig2 = mtcars %>% filter(am == 0) %>%
  ggplot(aes(wt, mpg)) +
  geom_point() + 
 theme_minimal(base_size = 15) + ggtitle('Theme B')

grid.arrange(fig1,fig2, ncol = 2)

Is there a way to display different themes for the facet argument in the same line of code?

If not, even just displaying different colour backgrounds for the facet argument will be helpful.

Answer 1

I would think facets are meant to have the same theme (the only thing changing between facets should only be a column that determines which data goes where and the axes based on certain settings free/fixed/etc.).

As @sam81 suggested, this answer is a good hacked solution based on a comment by hadley